The invention relates to a latent heat accumulator for use with a latent heat storage medium and with a heat exchange medium passing through and immiscible with the heat storage medium and having a specific weight different from, usually smaller than, that of the heat storage medium.
Latent heat accumulators, wherein a heat exchange medium immiscible with the latent heat storage medium is brought into a direct contact with the storage medium by passing through same, to eventually accumulate in a layer within the latent heat accumulator separate from the heat storage medium, have recently become used on an increased scale as heat accumulators with a high accumulation capacity (e.g. U.S. Pat. No. 4,086,958. In such latent heat accumulators, the heat exchange medium is usually charged from a conduit at a lower end of the storage medium batch or charge and then rises freely throughout the heat storage medium. In this fashion, a very intimate heat contact between the heat exchange and the heat storage medium is achieved. On the other hand, difficulties occur when the heat exchange medium passes through solidified regions of the heat storage medium. In such case, retardation of the heat exchange medium flow takes place. Substantial volumes of the heat exchange medium may become blocked within the solidified storage medium. The result is that the boundary layer between the heat storage medium and the heat exchange medium changes and, in an extreme case, the heat storage medium can even become drawn into the circulation of the heat exchange medium, to solidify therein and to give rise to substantial disturbance in operation of the overall system.
In order to avoid the problem, a great volume of heat exchange medium could be used. However, in so doing, the heat storage capacity of the device would be substantially reduced, while still not assuring a continuously distortion free operation.